Switching mechanism and method



Sept. 19, 1939.

POa/ T/ON A A5 R. W4 SORENSEN SWITCHING MECHANISM AND METHOD Filed April 13, 1936 3 Sheets-Sheet 1 [/v VE/VTOR RorAL PM \SORENSEN A TTORNEYf Sept. 19', 1939.

R. W. SORENSEN SWITCHING MECHANISM AND METHOD Filed April 13, 1936 3 Sheets-Sheet 2 Sept. 19, 9 R. w. SORENSEN SWITCHING MECHANISM AND METHOD Filed April 13, 1956 Sheets-Sheet 3 J .6. w W

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[NI/EN TOR Romz. M SORE/V-SEN MW! II/IZIJI/ ATTORNEY Patented 13?, 3.5955

UNITED STATES PATENT. OFFICE SWITCHING MECHANISM AND METHOD Royal W. Sorensen, Pasadena, Calif.

Application April 13, 1936, Serial No. 74,020

21 Claims. (01. 200-) My invention relates to a-novel method and apparatus for interrupting an electric circuit, particularly a high-voltage circuit in which an arc is formed during separation of the contact elements. More particularly, the invention relates to circuit breakers of the fluid-break type, and provides animproved method and apparatus for extinguishing the arc formed during the opening of the circuit.

In general, in the illustrative embodiment I employ one or more pairs of separable contact elements so related that both contact elements of each se arable pair move through a dielectric fluid, e5. er gaseous or liquid, in such a way as to cause the fluid to wipe or scavenge from both of the contact elements, and from the space between them, all ionized and arc-supporting mate- .rials.

According to past and present circuit breaker practice, the direction of contact element movement has been substantially along the arc axis. Such a modification produces arc lengthening only. The length of arc is an important factor in arc extinction, particularly for contact elements moving apart at high velocity in the presence of a fluid dielectric. This factor alone, however, has been found inadequate for circuit breakers which must'interrupt the high power electric circuits now in common use and it must be supplemented by auxiliary means more effective than the simple process of just lengthening the arc, if the arc is to be extinguished.

I have found it desirable in extinguishing the arc to cause an interposing of dielectric fluid in the space or gap between the separating contact elements in a manner such that the arc-bounding surfaces thereof are efiectively wiped or secured by the dielectric fluid. In this connection I have found it very desirable to use a smoothly-flowing dielectric fluid which flows across the contact surfaces without excessive turbulence. Such a relatively high-velocity andnon-turbulent flow immediately adjacent the contact surfaces is very effective in displacing the arc and wiping the arc and arc products therefrom.

It is an object of the present invention to utilize contact elements of stream-lined form. With such a. system any relative movement between the dielectric fluid and the contact elements will cause the dielectric fluid to flow along the streamlined surfaces without formation of voids or turbulence thereadjacent, the flow being at all times in contact with these surfaces to effectively displace and wipe the arc and are products thereimnt s t is ca l 9 t P e t venti n it is immaterial whether this relative movement between the contact elements and the dielectric fluid is obtained by moving the dielectric fluid. relative to the contact elements, ormoving the contact elements relative to the dielectric fluid. The latter form will be particularly illustrated herein, especially in view of its pertinency in relation to the other features of the invention.

In contrast to existing circuit breakers which merely move one contact .along the arc axis and thus permit continuance of the arc along the previously-formed arc path, my invention comprehends the movement of one, and usually both, contact elements in a direction transverse to the arc axis, or having a component of movement in such transverse direction. It is much more difflcult for the arc to persist between the contact elements if such movement is provided for. In the first place, it will be clear that if both contact elements are moved through the surrounding dielectric fluid, be that fluid a gas or a liquid, this motion causes the fluid to enter the gap and wipe from the contact elements the arc-sustaining products formed thereadjacent. In the second place, movement of both contact elements in such a manner causes elongation of the are into an arcuate path, the central portion of the arc lagging behind the contact elements and the are thus becoming longer and less stable as movement of the contact elements continues. In the third place, such motion of the contact elements sets up a flow of the dielectric fluid which tends to displace the are along the surface of the contact elements, and to finally wipe this are from the rear portion of these contact elements. In the fourth place, the contact elements continually move into a new portion of the dielectric fluid which contains none of the ionized or arc-sustaining materials. As a consequence the arc is quickly quenched.

It is an object of the present invention to provide a switch including two contact elements, and to simultaneously move both of these elements, as distinct from prior practice in which only one contact element was moved, the other being stationary.

It is another object of the present invention to provide an improved switch in which each of two contact elements is moved in such a way as to cause the dielectric fluid through which they .3

It is another object of the invention to move such contact elements away from the fluid which has been exposed to the arc and into a portion of the dielectric fluid which has not been thus exposed, and which new portion is, in consequence, in proper condition to quench the arc.

A further object of the invention is to provide for moving such contact elements in a direction deviating from the normal direction of the arc path. Preferably I move each of the contact elements in such a direction as to have one component of motion parallel to the are axis, thus tending to separate the contact elements, and another component transverse to this are axis, and it is another object of the present invention to provide such a system.

It is a further object of the present invention to provide a novel method and apparatus acting to cut off the are from the contact elements on which such an arc terminates.

Another object of the invention is to provide, in a double-sweep type of circuit breaken-contact elements which are stream-lined in such a manner as to cause the dielectric fluid through which the contact elements move to adhere closely to and blanket the surfaces of the contact elements as they move from closed-breaker posl tion to open-breaker position, thus forcibly wiping the arc-supporting elements from the surfaces of these contact elements in a manner not possible with turbulent flow of this dielectric fluid.

Another object of the invention is to provide a switch in which two contact elements can move into engagement in front of an arc-bounding edge of a suitable baffle or barrier, and during their separating motion move to a position beyond or to the rear of this arc-bounding edge so that the baflle is interposed between these contact elements, and the arc must move from one contact element to the other around the arcbounding edge if it is to persist.

Another object of the invention is to interpose between separating contact elements a suitable insulation barrier which is proof against rupture by the recovery voltage of the circuit being interrupted. Such an insulation barrier may comprise merely the insulating fluid, or it may comprise a solid barrier or baflle formed of insulation material, or it may include successive layers of solid and fluid insulating materials.

A further object of the invention is to provide a barrier between the points of closed position of adjacent sets of separable contact elements in a switch including a plurality of sets of contact elements, each set including two of these elements which can be brought into engagement, or disengaged.

Another object of the invention is to provide a novel system for equalizing electrostatic stresses and properly distributing the electrostatic flux to equally distribute the potential in a series of sets of contact elements.

A further object of my invention is to provide an improved double-sweep type of switch which will successfully and quickly interrupt a circuit, and which utilizes relatively light mechanisms and requires only a small power demand during switch operation.

Further objects of the invention lie in the features of construction to be hereinafter described, and further objects will be apparent to those skilled in the art from the following description.

For illustrative purposes, I will particularly describe, in this connection, a complete switch providing a plurality of sets of contact elements. Such a switch finds particular app ::tion in breaking high-voltage circuits,.thoug.1 it should be clear that the invention is not limited to this embodiment nor to the complete wrnbinations shown.

Referring to the drawings:

Fig. 1 is a diagram illustrating the principles of the invention.

Fig. 2 is a side view, partially in section, of one embodiment of the invention.

Fig. 3 is a vertical sectional view of the left half and central portion of the switch shown in Fig. 2.

Fig. 4 is a sectional View taken on the line 4-4 of Fig. 3', Fig. 3 being taken along the section indicated by the line 33 of Fig. 4.

Fig. 5 is a sectionalview showing certain of the guide means and contact members in elevation and is taken as indicated by the lines 5 --5 Fig. 9 is an enlarged detail of the engagement member.

The principles of the invention can best be understood by reference to Fig. 1 disclosing switch elements it] and H in contacting relationship at position A, and separating to break a circuit connected thereto, successive positions of these switch elements being indicated by positions B, C, D, and E. These contact elements are shown in section, each being stream-lined to provide a rather blunt leading edge I2, and a relatively sharp trailing edge 13. This form of contact element is believed to be new, regardless of the particular type of switch to which it is applied. If such a contact element is quickly moved througha dielectric fluid, or if the dielectric fluid is forcibly moved or jetted therealong, the stream-lined shape thereof will cause the dielectric fluid to flow smoothly therealong with practically no turbulence and to cling in wiping and scouring relationship with the stream-lined surface. Any are formed between the separating contacts, and thus terminating at the adjacent sides of the stream-lined contact elements, will thus tend to be forcibly displaced along and from the stream-lined surfaces by the wiping action of the smoothly-flowing dielectric fluid, regardless of whether the relative movement between the dielectric fluid and the contact element is caused by absolute movement of the contact element or by absolute movement of the dielectric fluid. All that is required with regard to the fundamental idea of utilizing stream-lined contact elements is the production of a relative movement which will effectively wipe the are from the contact elements, regardless of how this relative movement is obtained.

With particular reference to the type of switch in which both of the contact elements are moved through a relatively stationary body of dielectric fluid, Fig. 1 illustrates successive positions assumed by the contact elements In and H .in breaking the circuit. The first part of the interrupting cycle is to separate the contact elements a slight distance, this distance increasing throughout the cycle. In prior practice contact elements of different shape from that shown have been utilized and these contact elements have been so arranged that one contact element is stationary, the other being movable. The movable contact element in this prior practice has been moved directly from the stationary contact element, usually with linear motion. As soon as the contact elements separate an infinitesimal distance an arc will form between the stationary contact element and the movable contact element. This are will lie along an axis directly connecting the two contact elements, and in existing switches it is customary to move the movable contact element in a direction substantially parallel to this are axis. The result has been that the arc is drawn out, the contact elements being joined by an arc-sustaining filament or path containing ionized particles and arc-sustaining materials.

My invention comprehends movement in such a direction that a smooth-flowing stream of dielectric fluid is drawn into the space between the separating contact elements to effectively displace and wipe from these contact elements the are which has been formed. Preferably I move both of the contact elements into a zone containing dielectric fluid which has not been exposed to the arc and thus does not contain the ionized or arc-sustaining materials. My invention also comprehends movement of such contact elements in a direction substantially transverse to the arc axis, or in a direction deviating from the normal direction of this arc axis. Stated in other words, if we consider an imaginary plane C--C drawn tangent to contact surfaces, the present invention comprehends movement of the contact elements along paths which form angles of less than 90 with the imaginary plane CC. To move these contact elements In and II from each other along paths at right angles to the plane C-C,-for example in plane D-D, would merely result in movement along the arc axis which would merely draw out the arc without forcibly quenching same.

In accomplishing my novel movement, I prefer to move each contact element in such a direction that one component of this movement can be considered as being substantially parallel to the arc axis (e. g. in the plane D-D) while another component, usually larger, is directed transverse to the arc axis (e. g. parallel to the plane C--C) The result is that the contact elements l and II move in a direction indicated by the arrows l4 and I5 and substantially in planes passing through the leading and trailing edges thereof. These contact elements thus move considerably forward in assuming position 13 in which they are slightly separated. The are axis in this position is indicated by the dotted line I6, and an am will be formed along such an axis.

It will be clear, however, that the forward motion of the contact elements l0 and H will have a dual function. In the first place, these contact elements will move into a new portion of the dielectric fluid. In the second place, this forward motion of the contact elements I0 and II will cause a stream of the dielectric fluid to flow along and in pressural contact with the stream-lined surfaces. The relative velocity of this stream will be quite high, being only slightly lower than the forward velocity of the contact elements. The stream-lined shape avoids turbulence and consequent inevitable mixing of the ionized material with portions of the dielectric fluid in the gap other than in the arc path itself. Such a smoothfiowing stream serves several functions. Its proximity to the surface of the contact element insures that it will effectively scour or wipe from this surface the arc-sustaining materials, such as ionized particles. It will also forcibly move the arc rearward. in the gap and thus into a gap of greater length. In addition, it will bend the arc axis into arcuate form, thus lengthening the distance which must be bridged by the arc.

Thus, as the contact elements I0 and Il move toward and into position C, the arc path It will be shifted rearward in the now-widening gap, and will be considerably deformed into the arcuate shape shown at H. Additional movement toward and into position D will accentuate this effect.

If desired, this movement may be continued until the arc, if it still persists, extends between the trailing edges [3 of the contact elements l0 and I l, or until at least one' end of the arc is at one of these trailing edges. Further movement will cause the stream of dielectric fluid to wipe the are from this trailing edge, thus breaking the circult.

However, a more positive action will be obtained by positioning a barrier or baflle la in such a manner as to enter the gap between the separating contact elements and II; This may be accomplished by permitting engagement of the contact elements I0 and H only at a position in front of an arc-bounding edge I9 of the baflle and moving the contact elements so that one sweeps through a zone along one side of the baffle l8, and the other sweeps through a zone on the other side thereof. In position D I have shown the arc-bounding edge l9 just entering the gap between the separating contact elements. When the arc bounding edge reaches the existing arc, which in some instances may not have been previously extinguished, this are will be further elongated at a rate equal to the rate of forward movement of the contact elements. Thus, in position E the arc is represented by the nowelongated line 20, and it will be clear that the portion 2| of the arc cannot move forward any additional amount, being limited by the position of the arc-bounding edge IS. The are will thus be quenched either when the path indicated by the line 20 becomes sufficiently long that the arc cannot be sustained, or when the stream of dielectric fluid wipes the are from one or both trailing edges of the contact elements.

Best results are obtained by the use of a system which will interpose a plurality of barriers or baffles in the widening gap. In position E the contact elements l0 and II are shown as moving into the vicinity of auxiliary baffles 22 and 23 spaced from the baflie l8 to provide spaces 24 which are filled with the dielectric fluid. All of these bailles are preferably formed of insulating material, so that when the contact elements Ill and l I continue their movement from position E, there will be interposed in the gap therebetween successive layers of solid and fluid dielectric.

In illustrating one complete embodiment of the in Fig. 3 which illus rates in detail the left-hand portion 28a of the switch, the right-hand portion 2812 being a duplicate and thus not being disclosed. Referring to Fig. 3, the left-hand portion 28a of the housing 28 is shown as including, in addition to the central structure 30, an insulating member 32 with a mounting flange 32a and preferably formed of porcelain or other highresistance material. This left-hand portion oi. the housing 28 also includes a metallic end member 33 detachably connected to a flange 34 secured to the insulating member 32. This end member provides a chamber 35 which, in this embodiment of the invention, is filled with di-- electric oil to a level 36, a suitable vent 31 being provided. The right-hand end 28b of the housing 28 is formed with similar elements.

A sleeve 38, formed of fiber or other insulating material, extends along the insulating member 32 immediately inside thereof. This sleeve strengthens the insulating member, removing therefrom internal stresses which would otherwise be set up therein due to the overhanging nature of this end of the switch mechanism. It a1so removes from the insulating member 32 compressive strains which might be set up due to increased pressure in a chamber 40 defined therein when the switch opens. This chamber 40 is filled with the dielectric liquid and is bounded by an end plate 41 carrying a bearing 42 which permits communication between the chambers 35 and 40.

Similarly, the central structure 30 provides a chamber 43 closed by a cap 44 with a suitable vent 45, this chamber containing dielectric liquid, as does also the pedestal 26. Communication between the chambers 40 and 43 is provided through a bearing 41 mounted in an end plate 48 of the central structure 30.

Journalled in the bearings 42 and 41 is a shaft 50, shown as being of tubular form. A similar shaft is journalled in an identical manner in the right-hand portion 28b of the housing 28, and these shafts are operatively connected by a yoke 52 positioned in the chamber 43. In the embodiment illustrated, a 90 rotation of the shaft 50 is used to open and close the switch, this shaft being moved through this angle by a suitable operating means 53 of which the yoke 52 is a part. This operating means also is shown as including an operating rod 54 formed of insulating material and pivoted to the yoke 52 at 55 and extending to an actuating device 51 shown in Fig. 2. The function of this actuating device is to raise and lower the operating rod 54, thereby respec tively opening and closing the circuit. Various types of such actuating devices 51 are well known in the art and can be used in conjunction with the invention. Hydraulic, motor-driven, or spring-actuated devices maybe used, but I prefer to utilize an actuating device 51 which will very quickly move the shaft 50 through the desired angle of rotation when it is desired to trip the circuit breaker.

Diagrammatically I have shown the actuating device 51 as being opened by a compression spring 50 bearing against a plate 6| carried by the nice to current conditions in the circuit 3| in any well-known manner. When i is desired to again close the switch, the operating 54 pulled downward by any suitable closing mechanism 64 forming a part of the actuating device 51, this movement being continued until the latch 62 en gages the plate 6|. This closing mechanism may include a motor 65 operatively connected to the operating rod 54 through a clutch 58 and gear means 61, or other types of closing mechanism may be used. The actuating means 51 illustrated is merely diagrammatically shown, this type of device being disclosed merely to indicate one simple type of such actuating device.

Disposed in the chamber 40, and thus in the dielectric liquid therein, is a plurality of contact members arranged in sets or pairs. Three such sets are shown in the left-hand portion 280, the first set comprising contact members 10a and 10b, the second set comprising contact members Ho and lit), and the third set comprising contact members 12a. and 1217. Each of these contact members includes a contact element at the extended end thereof. Thus, contact members The and 1% provide contact elements 800 and 801), while the contact members Ho. and HI; provide contact elements Bio. and 81b, the contact members 12a and 12b correspondingly providing contact elements 82a and 82b. The contact elements of each set are in engagement in the position shown in Figs. 3 and 5. A corresponding series of contact members and contact elements are provided in the right-hand portion of the hous ing 28b.

Means is provided for moving the contact elements of each set in a direction having one component parallel to the arc axis therebetween when these contact elements are slightly separated, and having a second component transverse to such an arc axis. The first component is effective in separating or changing the spacing between the contact elements, while the second component is effective in moving these contact elements away from the are axis and into a new portion of the dielectric liquid. This motion can be visualized relative to Fig. 3 by'considering that the contact elements a. and 80b separate from each other as they move forward from the closed switch position shown in Fig. 3 into the open switch position shown in Fig. 6.

In the embodiment illustrated, this type of movement is. made possible by pivoting the contact members relative to the shaft 50 in such a manner that they tend to move through an ar-- cuate path concentric with the axis of the shaft 50 when this shaft is turned, and utilizing a cam means 85 to so guide the contact members that the contact elements separate during counterclockwise rotation of the shaft 50 as viewed in Fig. 4. To effectively pivot the several contact members to the shaft 50, I provide pins 86, 81, 88, and 89 extending through the shaft 50 with their axes parallel to each other but perpendicular to the axis of the shaft. As best shown in Figs. 3

and 4, each pivot means may include a sleeve 88a for journalling the corresponding pin and may be threaded to receive nuts 89 which bear against opposed portions of the shaft periphery, thereby locking the sleeve 88a in place. Each contact member provides a yoke 90 suitably bushed to be tor traversed by the contact members.

this embodiment of the invention to pivotally mount adjacent contact members of the first and second sets, namely, the contact members 10b and Ho. Similarly, the pin is used to pivotally mount the contact members H1) and 12a. Suitable means, such as nuts 9i, prevent axial movement of the pins in the corresponding sleeves 080. It will thus be apparent that this pivotal connection will permit swinging of each contact memher about the axis of the shaft 50.

Each of the contact members provides an outward-extending arm which carries the corresponding contact element. Such a contact element may be merely a continuation of the arm, or an attached contact element formed of certain arc-resistant materials may be utilized. If desired, the arc-bounding surfaces of the contact elements may be coated with arc-resistant material. I prei'er to make this arm of the contact member of stream-lined shape in cross section, as indicated in Fig. '1. It thus provides a blunt leading edge 92 and a relatively sharp trailing edge 93, a plane passing through these edges lying substantially in the plane of movement of this arm. This stream-lined shape of the arms is advantageous in facilitating quick opening of the switch, for such a stream-lined section presents a minimum of impedance to movement necessary in opening the switch. Similarly, I form the contact elements of stream-lined shape in cross-setclon, as indicated in Fig. 8. As therein shown, the contact elements 8Ia and Bib correspond to the contact elements I0 and II shown in diagrammatic Fig. 1. It is permissible to slightly flatten the stream-lined surfaces at the section of contact therebetween to insure a greater contact area, if desired. Such a slight flattening is showrr in accentuated degree in Fig. 8 and does not seriously interfere with the stream-lined character of the surfaces in insuring a smooth and substantially non-turbulent flow of dielectric liquid thereadjacent. Incidentally, stream-lining of the contact elements also facilitates quicker opening of the switch, though primarily these contact elements are stream-lined to secure the desirable smooth and clinging flow of dielectric liquids mentioned with reference to Fig. 1.

The cam means 85 utilized in guiding the movement of the contact members, and their associated contact elements, during 90 rotation of the shaft 50, is best shown in Figs. 3 to 6 inclusive. If desired, a single cam member of arcuate shape may be utilized which extends between, and is secured to, the members 4i and 48, such a cam member providing grooves or slots for receiving and guiding the various contact members. However, I prefer to form such a cam member in sections separated by baflle means 05, 96, and 91 to be later described in detail. Thus I have shown a cam section 99 extending between, and

secured to, the member 4i and the baffle means 85. Similarly, a cam section I00 extends between the baffle means 95 and 96, while a cam section IOI extends between the bafile means 96 and 91, a cam section I02 being similarly secured to and extending between the baffle means 91 and the member 40. As these cam sections are all designed along the same principles, it will suffice to describe in detail the cam section I00.

Referring to Figs. 3 to 6 inclusive, the cam section I00 is of arcuate form, being concentric with the axis of the shaft 50 and extending through an arcuate distance somewhat greater than the 90 rotation of the shaft and lying in that sec- This cam section I00 is preferably formed of insulating ma terial and may be of unitary or three-piece construction. A flange I04 secures it to the baffle structure 95, while a flange I05 secures it to the baifle means 90. This cam section I00 provides two grooves I01 and I08 which in effect intersect near theupper end thereof and diverge toward the lower end thereof in the embodiment shown. The contact member b moves along the groove I01 to be guided thereby, while the contact member 1Ia moves along the groove I08.

Considering the groove I01, this groove provides a cam surface I09 against which the contact member 10b bears during opening of the switch..

The groove I01 is only slightly larger than the transverse dimension of the contact member 10b so that a surface IIO serves as one portion of a means for retaining the contact member 10b adjacent the cam surface I09. Another portion of such means is preferably of resilient character and is indicated as an engagement member II2 biased to force the contact member 101) into resilient engagement with the cam surface I00 Just prior to the time that the switch assumes its closed position. Once the contact elements 00a and 80b come into engagement, further slight movement of the shaft will cause the contact member 10b to leave the cam surface I09, the engagement member II2 thus acting with the corresponding engagement member associated with the contact member 10a to force the contact elements 00a and 801) into resilient engagement.

If desired, the engagement member II2 may extend throughout the groove I09 to form the surface IIO. However, in the embodiment illus trated a notch H3 is provided in the groove I00 and the engagement member H2 is positioned therein as best shown in Figs. 5 and 9. This engagement member H2 is preferably of arcuate form corresponding to the arcuate shape of the cam section I00 and is secured thereto near the upper end of the notch H3. It is preferably formed of spring material and may be additionally biased to force the contact member 10b leftward by utilization of a spring II4 set in a suitable recess and compressed by any leftward movement of the free end of the engagement member I I2 as viewed in Fig. 3.

The grooves I01 and I08 may be continued as separate entities to the upper end of the cam section I00, but in the embodiment shown they intersect to form a space H5 in which the contact members 10b and H0, lie in adjacent relationship when the switch assumes its open position shown in Fig. -6.

In general, the cam section I00 should be formed of insulating material and the flange means I04 and I05 should be cut away adjacent the grooves I01 and I08 to permit free movement of the contact members. In the embodiment shown the cam section I00 is formed of three elements including two upper elements respectively secured by the flange means I04 and I05 to the baille means 95 and 96, the third and lower element being secured to both of the baille means 95 and 96 by lower portions of the flange means I04 and I05. However, a unitary construction may be utilized if desired.

The cam sections 99 to I 02 inclusive may be formed with grooves identical with those described relative to the cam section I00 except that the sections 99 and I02 require only one groove. If thus constructed, and if all of the contact members start to move at the same instant, the pairs of contact elements of each set the switch. However,

will open simultaneously and will move through corresponding arcuate paths during opening of by providing delayed opening of any pair of contact elements it is possible to nonsimultaneously form the arcs. So also, by mounting certainof the contact members loosely on their respective pivot pins it is possible to obtain a wiping action between the contact elements of any particular set before they sepa-- rate.

I have shown the end contact member 100 electrically connected to a stud I20 passing through the end member 33 by a flexible conductor I2I. This conductor may enter the end of the hollow shaft and extend outward to the pin 86 through an opening I2Ia. A terminal I22 secured thereto surrounds the pin 86, and to secure better electric connection I prefer to join the terminal I22 and the contact member 10a by a. flexible conductor I23.

Similarly, to better electrically connect the contact members 1Ib and 12a, I provide a flexible conductor I24 suitably secured thereto. A similar flexible conductor is secured between the contact members 10b and 1 Id.

The last contact element 12b of the series shown in Fig, 3 is electrically connected to a terminal I26 of a flexible conductor M1 by another flexible conductor I28. The conductor I21 enters an opening I29 of the shaft and extends from the end thereof into the'adjacent end oi" the shaft in the right-hand portion of the housing 28b. This conductor is connected to the first contact member of the series in this portion of the housing, the last contact member of this series being electrically connected to the circuit 3i. Thus, when the switch is in closed position shown in Fig. 3 and Fig. 5, current flows in series through the various contact members and the corresponding contact elements. When it is desired to interrupt the circuit the contact elements of the various pairs or sets separate. With the switch shown six arcs will be formed during this opening of the circuit, and whichever arc is first quenched by utilization of the principles discussed with reference to Fig. i will efiect interruption of the circuit.

To assist in interrupting these arcs, and to interpose an additional dielectric barrier in the widening gap during opening of the switch, I provide the baffle means 95, 96, and 91, best shown in Figs. 3 to 6 inclusive. Each oi these bafiie means may nclude a central baille i30 extending completely across the chamber 40' with the exception of an opening for the shaft 50 and an arc space provided by an opening I3I, best shown in Fig. 4. The corresponding contact elements come into engagement in the arc space defined by this opening. That side of the opening I3I towards which the separating contact elements move provides an arc-bounding edge I33. The central baflle I30 with its arc-bounding edge i33 corresponds to the baflle I8 and the arc-bounding edge I9 described with reference to Fig. 1. It will thus be clear that the contact elements come into engagement at a position in front of the arcbounding edge regardless of whether this edge is formed by an opening of the baflle or formed by any other terminal portion thereof.

Each of the baflle means is also shown as including auxiliary baflles I35 and I36 spaced from the central batlle I30 to provide spaces H31 and I38, corresponding to the spaces 24 mentioned with reference to Fig. 1. These spaces are filled with dielectric liquid, openings B39, being provided and I 36 to insure filling of these spaces.

near the upper ends of the auxiliary baflles I35 These auxiliary bailies also extend completely across the chamber 40 excepting only that space defined by openings I40 which are slightly larger than the opening III. The walls of these openings I40 and I3I are suitably beveled, as shown, to so commodate the movement of the contact mem-' here. While it is preferable to spread the contact elements of any particular set a sufllcient distance to clear these beveled edges of the bailles, it is possible in some instances to permit contact therebetween, even maintaining contact between the contact elements until they are separated by such a baffle. However, such a mode of operation is not conducive to thedesirable smooth and nonturbulent flow between the contact elements mentioned with reference to Fig. 1.

Various means may be utilized for retaining the baffles I30, I35, and I36 inplace. As shown, these bailles are partially supported by the cam sections .33 to I02. In addition, the edges of these baflles I30, I35, and I36 are retained in four peripheral positions by short blocks I45groovecl to retain these bailles and secured to the sleeve 30 as by screws I46. Positive spacing of these baffles is insured thereby and also by spacing pins I41 extending across the spaces I31 and I38 and being retained in place by any suitable means such as by extending into corresponding indentations in the bailles.

It will thus be clear that each contact element moves from a position in front of an arc-bounding edge to a position to the rear thereof when the switch is moved from closed to open position. When in open position, or in an intermediate position after passing the arc-bounding edge, these contact elements will thus be separated by a dielectric barrier of which a solid insulating material is a part. During the latter part of this movement this barrier will include successive layers of liquid and solid dielectric. Such successive layers have been found to be very advantageous especially in preventing flash-over or puncture due to the recovery voltage which often builds up to very high values immediately after the circuit has been interrupted. However, another important advantage of such baflles is that described with reference to Fig. 1 and involving the clor-- cation of the are for it is clear that this are must extend around the arc-bounding edge if it is to persist.

As an additional precaution to prevent any pos-- sibility of an are forming between the contact ele ments a and Bib, or between corersponding contact elements of other portions of the series. I interpose a barrier or baflle means I50 between adjacent sets or pairs of contact elements whe the contact elements of these pairs are in en gagement. Such a baffle means I50 is interposed between the contact elements 80b and 8Ia, ant" also between the contact elements 8Ib and 82a, at; shown in Fig. 3. The baflie means I50 may in clude a central batlle I5I and auxiliary baffles I52 and I53 spaced from each other by means aim ilar to those provided in the baiile means pro viously described. A grooved block of insulating: material I55 may be positioned in the lower end of the chamber 40 to retain each of the baffle means I 50, this block extending between the bafllc means and 96, and between the baffle means 96 and 91. The size of such bafile means I50 is not critical, it being sufiicient if this baffle means extends in the zone occupied by the con-- tact elements when in closed position. However,

this baille means is made sumciently large to elongate any possible are path between the contact elements 80a and Gib, for instance. In many instances these baflle means I" can be dispensed with.

I find it desirable to utilize in conjunction with each of the baille means 95, 96, and 91 a ring or disc I60. As shown, such a ring is attached by any suitable means to the central bafile I10 of each baille means, being coaxial with the axis of the shaft 50. Each of these rings is preferably formed of conducting material and is split at one section so as not to form a short-circuited turn. The function of such rings or discs is to divide the column of dielectric fluid surrounding the series of separable contact members electrostatically in such a way to equalize the voltage stress across the several pairs or sets of contact elements in series when the breaker is in opencircuit position.

It should not be understood that the invention is limited to the type of switch disclosed in Fig. 2.

.It can, with equal propriety, be utilized in conjunction with switches of the grounded tank type.

Nor is it necessary from the fundamental aspects of the invention to utilize a plurality of sets of contact members and elements. Further, while the invention has been particularly described with reference to a switch filled with dielectric liquid, it will be clear that any dielectric fluid, be it liquid or gas, can be utilized.

It should be further clear that various other mechanisms can be utilized for moving the contact elements in a manner discussed with reference to Fig. 1. While the invention has been particularly described relative to a system in which the contact members are pivoted to a shaft, and are guided by a suitable cam means, various linkages or cam structures can be utilized to effect this movement. In this connection it should be further apparent that the invention is not limited to movement of the contact elements through an arcuate path. By utilization of other mechanisms, movement of these contact elements in a flat plane, as dis tinct from an arcuate plane, can be eflected. However, a system utilizing a rotatable shaft has been found to be very satisfactory, though it will be clear that a switch such as shown in the illustrative embodiment can be designed to move from closed to open position with any desired angular displacement of the shaft 50, the 90 displacement being herein disclosed for illustrative purposes only.

My invention involves a new conception in the switch art, as illustrated in Fig. 1. The contact elements Ill and II are initially in intimate electrical contact, as shown in position A. The elements are pulled away from each other into position B, forming a gap l8 between the elements I. and II and an arc will tend to persist in this gap. The elements I0 and II are, however, not only separated from each other, but they are simultaneously moved in a direction lateral or, roughly, at right angles to the gap. Using many common types of dielectric media, such as switch oil which is a petroleum distillate, the arc tends to gasify the oil. The gas bubbles so formed are of low electrical resistance and any arc formed therethrough tends to persist or reform. By moving the contact elements Ill and II bodily through the dielectric medium the gas bubbles are left behind, the elements moving into fresh cold oil having a high dielectric value. This fresh cold oil tends to quench the arc and prevent the formation of new arcs. I

While many of the features of the invention are particularly applicable to a system in which both contact elements of any particular set or pair move through the dielectric fluid, certain of the features of this invention are not limited thereto. For instance, the stream-lining of the contact elements can be utilized in conjunction with various blast-type circuit breakers, as can certain other features of the invention. Nor is it always essential to the invention to move both contact elements of any particular set or pair. though particularly advantageous results will accrue from such simultaneous movement.

Various changes and modifications can be made without departing from the spirit of the invention as set forth in the appended claims.

I claim as my invention:

1. In combination in a switch for interrupting an electric circuit by forming an arc in a dielectric fluid and then interrupting said arc: a pair of contact elements in said dielectric fluid; a shaft operatively connected to the contact elements to move both of said contact elements side by side around the axis of said shaft; and means for spreading said contact elements from each other when said shaft is moved at a rate which is materially less than the rate of movement of said contact elements side by side.

2. In combination in a switch for interrupting an electric circuit by forming an arc in a dielectric fluid and then interrupting said arc: a pair of contact members in said dielectric fluid, each providing a contact element; a shaft; means for rotatably mounting said shaft; means for securing said contact members to said shaft whereby angular movement of said shaft moves said contact elements about the axis of said shaft; means operatively connected to said contact members for spreading said contact elements from each other when said shaft is turned in a given direction to move said contact elements from contacting position into non-contacting position; means for turning said shaft; and means electrically connecting said contact elements to said electric circuit.

3. In combination in a switch for interrupting an electric circuit by forming an arc in a dielectric fluid and then interrupting said arc: a pair of contact members providing contact elements positioned in said dielectric fluid and engageable with each other; a shaft operatively connected to said contact members to simultaneously move said contact elements about the axis of said shaft in the same direction; cam means for separating said contact elements during movement thereof by said shaft; and means electrically connecting said contact elements to said circuit.

4. A combination as defined in claim 3 including means for-turning said shaft and including means for pivoting said contact members to said shaft whereby said contact elements move about the axis of said shaft when said shaft is turned.

5. A combination as defined in claim 3 including means for turning said shaft and including means for pivoting said contact members to said shaft whereby said contact elements move about the axis of said shaft when said shaft is turned, and in which said cam means includes a cam structure spaced from said shaft and providing cam surfaces thereon engaged by said contact members to guide same during said movement of said contact elements about said axis of said shaft.

6. In combination in a switch for interrupting an electric circuit by forming an arc in a dielectric fluid and then interrupting said arc: a baffle means in said dielectric fluid and providing an arc-bounding edge; ashaft extending adjacent said baflie means; means for rotatably mounting said shaft; a pair of contact members extending outward from said shaft and providing contact elements engageable with each other at a position in front of said arc-bounding edge, said contact elements moving about the axis of said shaft when said shaft is angularly moved; means operatively connected to said contact members for spreading said contact elements from engagement in front of said arc-bounding edge as they move under the influence of the angular displacement of said shaft to spread some sufficiently to clear said arc-bounding edge when they sweep past this edge during said angular displacement of said shaft; means for turning said shaft to cause said angular displacement, said means moving said shaft sufficiently to move said contact elements into non-contact= ing position to the rear of said arc-bounding edge; and means electrically connecting said contact elements to said electric circuit.

7. In combination in a switch for interrupting an electric circuit by forming an arc in a di= electric fluid and then interrupting said arc: a housing containing said dielectric fluid; a shaft rotatably mounted in said housing; a series of contact members in said housing, each providing a contact element and each extending outward from said shaft said contact members being arranged in sets, each set including two contact members; means electrically connecting together adjacent contact elements of adjacent sets; means for holding the two contact elements of each set in engagement when said switch is in closed position; means electrically connecting the end contact members of the series to said electric circuit whereby current flows through all of said contact members in series when said switch is in said closed position; means to rotate said shaft to move said contact elements; and means for separating said contact elements of each set during movement of the corresponding contact members by said shaft.

8. In combination in a switch for interrupting an electric circuit by formng an arc in a dielectric fluid and then interrupting said arc: a

housing containing said dielectric fluid; a shaft' rotatably mounted in said housing; a series of contact members in said'housing, each providing; a contact element and each extending outward from said shaft; pivot means spaced along said shaft for pivoting said contact members thereto to pivot relative to said shaft about axes transverse to the axis of said shaft, said contact members being arranged in sets, each set including two contact members; means electrically connecting together adjacent contact elements of adjacent sets; a cam means providing cam surfaces for said contact members and with which said contact members slidably engage, thereby controlling the pivoting of said contact members on said pivot means, the cam surfaces corresponding to the contact members of each set being closer together at one end than at the other end thereof whereby when said contact members of this set are at said one end of the corresponding cam surfaces the contact elements of these contact members are in engagment to assume a closed switch position and when these contact members are at the other end of said cam surfaces these contact elements are spaced from each other to assume an open switch position; and means electrically connecting the and contact members of said series to said circuit.

9. In combination in a switch for interrupting an electric circuit by forming an arc in a dielectric fluid and then interrupting said arc: a pair of diverging cam surfaces closer together at one end than at another end; two contact members respectivelyengaging said cam surfaces to contact each other when at said one end of said cam surfaces and to be separated from each other when at the other end of said cam surfaces; means for movably mounting said contact members to permit simultaneous movement along said cam surfaces; and means for moving said contact members along their respective cam surfaces.

10. In combination in a switch for interrupting an electric circuit by forming an arc in a dielectric fluid and then interrupting said arc: a series of movable contact members arranged in sets, each set including two adjacent contact members, the contact members of each set providing engageable contact elements which when in en gagcment represent a closed switch position and which when not in engagement represent an open switch position; means connecting said sets of contact members in series with the circuit to be interrupted; a plurality of baille means formed of insulating material and positioned to extend between the contact elements of each set when said contact elements are in open switch position; and potential-equalizing means associated with each of said baffle means to substantially equalize the voltage across said sets of contact elements when in open switch position, each of said means including a conducting element electrically independent to said circuit to be interrupted.

ii. In combination in a high-voltage circuit breaker for interrupting an electric circuit by forming an arc in a dielectric fluid and subseouently interrupting said arc: a baffle; two contact elements in said dielectric fluid and electrically connected in said circuit; two contact members carrying said elements; and means for moving said members from a position at which said contact elements are in mutual contact to a position at which said contact elements are on opposite sides of said baffle, said means including means for pivoting said members about axes spaced from said contact elements and extending non-parallel with respect to the face of said baffle.

12. In combination in a switch for completing and interrupting an electric circuit by forming an arc in a dielectric fluid and subsequently interrupting said arc: a housing containing a dielectric fluid; baffles dividing said housing into a plurality of chambers, each baffle having an aperture; a pair of movable contact elements in each of said chambers; means for electrically connecting together the contact elements of the pair in each chamber; means for engaging the contact elements in adjacent chambers in zones defined by said apertures to complete said circuit; and means for separating said contact elements and moving same from the zones defined by said apertures to interrupt said circuit.

13. In combination in a switch for interrupting an electric circuit: a battle means providing an arc-bounding edge; a pair of contact elements electrically connected to said circuit and engaging each other at a position beyond and in front 14. A combination as deflned in claim 13 in which said last-named means includes means for separating said contact elements during movement toward said arc-bounding edge a suiflcient distance to clear said baflie and its arcbounding edge.

15. In combination in a switch for interrupting an electric circuit by forming an arc in a dielectric fluid and then interrupting said arc: a pair of contact elements electrically connected to the circuit to be interrupted and positioned in said dielectric fluid; and means for simultaneously moving said contact elements side-byside through arcuate paths in said dielectric fluid about a common axis spaced from said contact elements including means for separating said contact elements during this arcuate movement to form and interrupt said arc.

16. In combination in a switch for interrupting a high-voltage electric circuit: a pair contact elements positioned in a dielectric fluid; a pair of contact members respectively carrying said contact elements; means for advancing said contact members to move said contact elements side by side through said dielectric fluid from a closed-switch position to an open-switch position; and means cooperating with said first named means for separating said contact elements during this advancement to form a widening gap, the rate oi widening oi said gap being very materially less than the rate oi advancement of said contact elemen'is through said dielectric fluid throughout the circuit interrupting movement of said contact elements.

17. In combination in a switch for interrupting a high-voltage electric circuit: a pair of contact elements positioned in a dielectric fluid; a pair of contact members respectively carrying said contact elements; means for advancing said contact members to move said contact elements side by side through said dielectric fluid from a closed-switch position to an open-switch position; and means cooperating with said first named means ior separating said contact elements during this advancement to form a widening gap, the rate of widening of said gap being very materially less than the rate of advancement or said contact elements through said dielectric fluid throughout the circuit interrupting movement of said contact elements. said contact elements being streamlined to retard turbulence of said dielectric fluid during advancement 01' said contact elements.

18. In combination in a switch for interrupting a high-voltage electric circuit: a pair of contact elements positioned in a dielectric fluid; a pair of contact members respectively carrying said contact elements; means for advancing said contact members to move said contact elements side by side through said dielectric fluid from a closed-switch position to an open-switch position; means cooperating with said first named means for separating said contact elements during this advancement to form a widening gap, the rate of widening of said gap being very materially less than the rate of advancement of said contact elements through said dielectric fluid throughout the circuit interrupting movement of said contact elements; and a stationary barrier extending between the paths of said contact elements so that said contact elements are positioned upon opposite sides 01' said barrier when in open-switch position.

19. In combination in a switch for interrupting a high-voltage electric circuit: a pair of contact elements positioned in a dielectric fluid; a pair of contact members respectively carrying said contact elements; drive means for simultaneously moving said contact members to move said contact elements substantially side by side from closed-switch position to open-switch position; and guiding means for said members for moving said contact elements in diverging paths to separate said contact elements and provide a rate of side by side movement oi said contact elements which is substantially greater than the rate of separation or said contact elements throughout the interruption of said circuit.

20. The method of interrupting a high-voltage electric circuit, which comprises: separating a pair oi! contact elements in series in said circuit and positioned in a dielectric fluid to form an are between said elements; and simultaneously rapidly moving said contact elements through said dielectric fluid side by side substantially transverse to the separating movement 0! said elements at a rate substantially greater than the rate of separating movement of said contact elements until said arc is broken by being elongated and swept from said elements.

21. The method oi. interrupting a high-voltage electric circuit, which comprises: separating a pair of contact elements in series in said circuit andpositioned in a dielectric fluid to form an are between said elements; and simultaneously rapidly moving said contact elements through said dielectric fluid side by side substantially transverse to the separating movement oi said elements to oppositesides of a solid dielectric barrier at a rate substantially greater than the rate of separating movement oi. said contact elements until said are is broken by being elongated and swept from said elements.

ROYAL W. BORENSEN. 

